No abstract

During a prospective study of pregnancies in women with systemic lupus erythematosus, we examined the relation between antibody to cardiolipin, measured by the enzyme-linked immunosorbent assay, and midpregnancy fetal distress, identified by abnormal results of antepartum fetal heart-rate testing or by fetal death. All of nine patients with lupus and this complication had abnormally high antibody levels (mean, 212.3 +/- 55.3 units), as compared with values in normal nonpregnant women (28.2 +/- 10.1 units). None of 12 pregnant patients with lupus but without this complication had antibody levels above 50 units (mean, 27.5 +/- 3.4 units; P less than 0.005 vs. women with lupus and fetal distress); 4 of 12 pregnant subjects without lupus had antibody levels above 50 units (mean, 42.5 +/- 11.0), and fetal death occurred in the subject with the highest level. The mean antibody level in 12 nonpregnant patients with lupus was 117.4 +/- 35.0 units. Two patients who had lupus anticoagulant but not clinical lupus, both with histories of prior fetal death, also had high antibody levels; fetal death occurred in one, and spontaneous fetal bradycardia in the other. Antibody to cardiolipin was loosely linked to a history, but not the simultaneous presence, of demonstrable lupus anticoagulant or thrombocytopenia, and could be detected as early in pregnancy as either anticoagulant or thrombocytopenia. We conclude that measurement of antibody to cardiolipin is the most sensitive assay to predict fetal distress or death in patients with systemic lupus erythematosus and may be of pathogenetic importance in this syndrome.

Tang Y, Saul A, Gur M, Goei S, Wong E, Ersoy B, Snodderly DM. Eye position compensation improves estimates of response magnitude and receptive field geometry in alert monkeys. J Neurophysiol 97: 3439 -3448, 2007. First published March 7, 2007 doi:10.1152/jn.00881.2006. Studies of visual function in behaving subjects require that stimuli be positioned reliably on the retina in the presence of eye movements. Fixational eye movements scatter stimuli about the retina, inflating estimates of receptive field dimensions, reducing estimates of peak responses, and blurring maps of receptive field subregions. Scleral search coils are frequently used to measure eye position, but their utility for correcting the effects of fixational eye movements on receptive field maps has been questioned. Using eye coils sutured to the sclera and preamplifiers configured to minimize cable artifacts, we reexamined this issue in two rhesus monkeys. During repeated fixation trials, the eye position signal was used to adjust the stimulus position, compensating for eye movements and correcting the stimulus position to place it at the desired location on the retina. Estimates of response magnitudes and receptive field characteristics in V1 and in LGN were obtained in both compensated and uncompensated conditions. Receptive fields were narrower, with steeper borders, and response amplitudes were higher when eye movement compensation was used. In sum, compensating for eye movements facilitated more precise definition of the receptive field. We also monitored horizontal vergence over long sequences of fixation trials and found the variability to be low, as expected for this precise behavior. Our results imply that eye coil signals can be highly accurate and useful for optimizing visual physiology when rigorous precautions are observed.

Down syndrome cell adhesion molecules (dscam and dscaml1) are essential regulators of neural circuit assembly, but their roles in vertebrate neural circuit function are still mostly unexplored. We investigated the functional consequences of dscaml1 deficiency in the larval zebrafish (sexually undifferentiated) oculomotor system, where behavior, circuit function, and neuronal activity can be precisely quantified. Genetic perturbation of dscaml1 resulted in deficits in retinal patterning and light adaptation, consistent with its known roles in mammals. Oculomotor analyses revealed specific deficits related to the dscaml1 mutation, including severe fatigue during gaze stabilization, reduced saccade amplitude and velocity in the light, greater disconjugacy, and impaired fixation. Two-photon calcium imaging of abducens neurons in control and dscaml1 mutant animals confirmed deficits in saccade-command signals (indicative of an impairment in the saccadic premotor pathway), whereas abducens activation by the pretectum-vestibular pathway was not affected. Together, we show that loss of dscaml1 resulted in impairments in specific oculomotor circuits, providing a new animal model to investigate the development of oculomotor premotor pathways and their associated human ocular disorders.